U.S. patent number 5,565,512 [Application Number 08/620,435] was granted by the patent office on 1996-10-15 for fluorine-containing elastomer composition.
This patent grant is currently assigned to Nippon Mektron, Limited. Invention is credited to Futoshi Kumiya, Satoru Saito, Haruyoshi Tatsu.
United States Patent |
5,565,512 |
Saito , et al. |
October 15, 1996 |
**Please see images for:
( Certificate of Correction ) ** |
Fluorine-containing elastomer composition
Abstract
A fluorine-containing elastomer composition comprising a
terpolymer of tetrafluoroethylene, perfluoro(lower alkyl vinyl
ether) and cyano group-containing (perfluorovinylether), and a less
expensive of the ammonium salt of organic or inorganic acid as a
curing agent produce a vulcanization product having good heat
resistance and solvent resistance, and when no carbon black, etc.
are contained in the composition for curing, transparent
vulcanization product having satisfactory physical properties are
obtainable.
Inventors: |
Saito; Satoru (Kitaibaraki,
JP), Kumiya; Futoshi (Hitachi, JP), Tatsu;
Haruyoshi (Hitachi, JP) |
Assignee: |
Nippon Mektron, Limited (Tokyo,
JP)
|
Family
ID: |
27309010 |
Appl.
No.: |
08/620,435 |
Filed: |
March 22, 1996 |
Foreign Application Priority Data
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Mar 31, 1995 [JP] |
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7-099655 |
Aug 11, 1995 [JP] |
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7-227017 |
Nov 30, 1995 [JP] |
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7-336103 |
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Current U.S.
Class: |
525/340;
525/326.3; 525/341; 525/353; 525/359.3; 525/359.4; 525/374;
525/378; 525/379 |
Current CPC
Class: |
C08K
3/24 (20130101); C08K 5/098 (20130101); C08K
3/24 (20130101); C08L 27/18 (20130101); C08K
5/098 (20130101); C08L 27/18 (20130101) |
Current International
Class: |
C08K
3/00 (20060101); C08K 5/00 (20060101); C08K
3/24 (20060101); C08K 5/098 (20060101); C08F
008/30 () |
Field of
Search: |
;525/340,341,353,359.3,359.4,374,378,379 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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59-109546 |
|
Jun 1984 |
|
JP |
|
63-5409 |
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1988 |
|
JP |
|
Primary Examiner: Lipman; Bernard
Attorney, Agent or Firm: Kenyon & Kenyon
Claims
What is claimed is:
1. A fluorine-containing elastomer composition, which comprises a
terpolymer of tetrafluoroethylene, perfluoro(lower alkyl vinyl
ether) and cyano group-containing (perfluorovinylether), and an
ammonium salt of organic or inorganic acid as a curing agent.
2. A fluorine-containing elastomer composition according to claim
1, wherein the terpolymer is a terpolymer of tetrafluoroethylene,
perfluoro(methyl vinyl ether) and CF.sub.2 .dbd.CFO (CF.sub.2)nCN,
wherein n is an integer of 2 to 12, or CF.sub.2 .dbd.CFO [CF.sub.2
CF(CF.sub.3)O]nCF.sub.2 CF(CF.sub.3)CN, wherein n is 0 or an
integer of 1 to 4, CF.sub.2 .dbd.CFO[CF.sub.2
CF(CF.sub.2)O]m(CF.sub.2)nCN, wherein n is an integer of 1 to 4 and
m is an integer of 1 to 2, or CF.sub.2 .dbd.CFO(CF.sub.2)nOCF
(CF.sub.3)CN, wherein n is an integer of 2 to 4.
3. A fluorine-containing elastomer composition according to claim
1, wherein the terpolymer is a terpolymer comprising 50 to 75% by
mole of tetrafluoroethylene, 49.8 to 25% by mole of perfluoro(lower
alkyl vinyl ether) and 0.2 to 5% by mole of cyano group-containing
(perfluorovinylether), sum total being 100% by mole.
4. A fluorine-containing elastomer composition according to claim
1, wherein the ammonium salt of organic acid is an ammonium
polyfluorocarboxylate, an ammonium polyfluorosulfonate, an ammonium
polyfluoroalkyl group-containing phosphate, phosphonate or
sulfonate, ammonium carboxylate or sulfonate, or an ammonium
phosphate or phosphonate.
5. A fluorine-containing elastomer composition according to claim
1, wherein the ammonium salt of inorganic acid is ammonium sulfate,
ammonium carbonate, ammonium nitrate or ammonium phosphate.
6. A fluorine-containing elastomer composition according to claim
1, wherein 0.2 to 5 parts by weight of the ammonium salt of organic
or inorganic acid is used per 100 parts by weight of the
terpolymer.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a fluorine-containing elastomer
composition, and more particularly to a cross-linkable composition
of fluorine-containing elastomer having cyano groups as
cross-linkable groups.
2. Related Prior Art
JP-A-59-109546 discloses a fluorine-containing elastomer
composition comprising a terpolymer of tetrafluoroethylene,
perfluoro(methyl vinyl ether) and cyano group-containing
(perfluorovinylether) represented by the following general
formula:
wherein n is an integer of 1 to 2 and m is an integer of 1 to 4,
and a bis(aminophenyl) compound represented by the following
general formula as a cross-linking agent: ##STR1## wherein A is an
alkylidene group having 1 to 6 carbon atoms, a perfluoroalkylidene
group having 1 to 10 carbon atoms, SO.sub.2 group, O group, CO
group or a carbon-carbon bond capable of directly bonding two
benzene rings, and X and Y each are hydroxyl group or amino group.
However, the bis(diamino-phenyl) compound or bis(aminophenol)
compound is expensive for the industrial scale application.
JP-A-55-98212 discloses use for tetraphenyl tin as a curing agent
for such a fluorine-containing elastomer having cyano groups, but
the tetraphenyl tin is toxic and its use is not preferable.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a
fluorine-containing elastomer composition capable of producing
vulcanization products having a good resistance to a solvent, which
comprises a less expensive compound than a bis(diaminophenyl)
compound or bis(aminophenol) compound as a curing agent for a
fluorine-containing elastomer having cyano groups as cross-linkable
groups.
According to the present invention, there is provided a
fluorine-containing elastomer composition, which comprises a
terpolymer of tetrafluoroethylene, perfluoro(lower alkyl vinyl
ether) and a cyano group-containing (perfluorovinylether), and an
ammonium salt of organic or inorganic acid as a curing agent.
DETAILED DESCRIPTION OF THE INVENTION
Terpolymers of tetrafluoroethylene, perfluoro(lower alkyl vinyl
ether) and cyano group-containing (perfluorovinylether) for use in
the present invention includes, for example, terpolymers comprising
50 to 75% by mole of tetrafluoroethylene, 49.8 to 25% by mole of
perfluoro(lower alkyl vinyl ether) or perfluoro-(lower alkoxy-lower
alkyl vinyl ether) and 0.2 to 5% by mole of cyano group-containing
(perfluorovinylether) as a cross-linking site monomer, sum total
being 100% by mole.
Perfluoro(lower alkyl vinyl ether) for use in the present invention
includes, for example, perfluoro(methyl alkyl vinyl ether).
Cyano group-containing (perfluorovinylether) serving to form
cross-linkable groups in the terpolymer includes, for example, the
following compounds:
(a) CF.sub.2 .dbd.CFO(CF.sub.2).sub.n CN
(n: an integer of 2 to 12)
[as disclosed in U.S. Pat. Nos. 3,546,186; 3,114,778]
(b) CF.sub.2 .dbd.CFO[CF.sub.2 CF(CF.sub.3)O]CF.sub.2
CF(CF.sub.3)CN
(n: 0 or an integer of 1 to 4)
[as disclosed in U.S. Pat. Nos. 3,852,326; 3,933,767]
(c) CF.sub.2 .dbd.CFO[CF.sub.2 CF(CF.sub.3)O].sub.m
(CF.sub.2).sub.n CN
(n: an integer of 1 to 4; m: an integer of 1 to 2)
[as disclosed in U.S. Pat. Nos. 4,138,426; 4,281,092]
(d) CF.sub.2 .dbd.CFO(CF.sub.2).sub.n OCF(CF.sub.3)CN
(n: an integer of 2 to 4)
[as disclosed in Japanese Patent Application No. 6-295548]
The above-mentioned cyano group-containing (perfluorovinylether)
compound (d) can be synthesized, for example, through the following
reaction route: ##STR2##
As given by the foregoing reaction route, oxalyl difluoride,
perfluoromalonyl difluoride or perfluorosuccinyl difluoride is
subjected to addition reaction with 2 equivalent of
hexafluoropropylene oxide in the presence of a cesium fluoride
catalyst, and the resulting addition reaction product is thermally
decomposed in the presence of sodium carbonate to obtain a
monovinyl compound. Then, the monovinyl compound is esterified
through reaction with an alcohol such as methanol in the presence
of a HF trapping agent such as sodium fluoride, followed by
addition of bromine to the double bond to protect it and by
reaction with ammonia to amidize the protected compound. Then, the
amide compound is dehydrated in the presence of phosphorus
pentoxide with heating to cyanize the compound. Finally the cyano
compound is subjected to debromination reaction in the presence of
zinc to obtain the desired cyano group-containing
(perfluorovinylether) compound (d).
The terpolymer can be further copolymerized with fluoroolefins,
olefins or vinyl compounds to such a degree as not to inhibit the
copolymerization reaction or deteriorate physical properties of
vulcanization products, for example, not more than about 20% by
mole on the basis of the terpolymer. Fluoroolefins include, for
example, vinylidene fluoride, monofluoroethylene,
trifluoroethylene, trifluoropropylene, pentafluoropropylene,
hexafluoropropylene, hexafluoroisobutylene, chlorotrifuoroethylene,
dichlorodifluoroethylene, etc. Olefins or vinyl compounds include,
for example, ethylene. propylene, 1-butene, isobutylene, methyl
vinyl ether, ethyl vinyl ether, butyl vinyl ether, cyclohexyl vinyl
ether, vinyl acetate, vinyl propionate, vinyl chloride, vinylidene
chloride, trifluorostyrene, etc.
Curing agent for use in the present invention includes, for
example, the following compounds:
(1) Ammonium polyfluorocarboxylates: ##STR3## (2) Ammonium
polyfluorosulfonates: ##STR4## wherein Rf: perfluoroalkyl groups
having C.sub.1 to C.sub.20 which can contain an ether bond
therein.
(3) Ammonium polyfluoroalkyl group-containing phosphates,
phosphonates or sulfonates: ##STR5## wherein Rf: perfluoroalkyl
groups having C.sub.1 to C.sub.20 which can contain an ether
bond;
R: a lower alkyl group.
(4) Ammonium carboxylates or sulfonates: ##STR6## wherein R:
hydrogen atom or an alkyl or alkylene group having C.sub.1 to
C.sub.30.
(5) Ammonium phosphates or phosphonates:
ROPO(ONH.sub.4).sub.2
RPO(ONH.sub.4).sub.2
RR'PO(ONH.sub.4)
ROP(ONH.sub.4).sub.2
(RO)(R'O)P(ONH.sub.4)
wherein R and R': alkyl groups having C.sub.1 to C.sub.30.
(6) Ammonium salts of inorganic acids:
Ammonium sulfate
Ammonium carbonate
Ammonium nitrate
Ammonium phosphate
In view of dispersibility in the fluorine-containing elastomer and
physical properties of vulcanization products, ammonium salts of
organic acids, particularly ammonium polyfluorocarboxylates, are
preferably used among the foregoing ammonium salts.
About 0.2 to about 5 parts by weight, preferably about 0.5 to about
3 parts by weight, of the ammonium salt of organic or inorganic
acid is added to 100 parts by weight of the terpolymer.
The fluorine-containing elastomer composition comprising the
above-mentioned essential components can further contain an
inorganic filler such as carbon black, silica, etc.; oxides or
hydroxides of divalent metal such as lead oxide (PbO), zinc oxide,
magnesium oxide, calcium hydroxide, etc.; acid receptor such as
stearate, hydrotalcite, etc.; pigments; processing aids;
plasticizers; and other necessary additives, when desired. The
composition can be prepared by kneading at about 30.degree. to
about 100.degree. C. by roll, kneader, Bambury mixer or the like.
Curing of the composition is carried out by heating at about
150.degree. to about 220.degree. C. for about 5 to about 60 minutes
in a compression molding machine, etc. Secondary vulcanization can
be carried out in air or in a nitrogen gas atmosphere at about
200.degree. to about 300.degree. C. for about 10 to about 50
hours.
Fluorine-containing elastomer having cyano groups as cross-linkable
groups can be cured by an ammonium salt of organic or inorganic
acid, which is less expensive than bis (diaminophenyl) compound or
bis(aminophenyl) compound, and the resulting vulcanization products
have good resistance to heat and solvents. When no carbon black,
etc. are contained in the curable composition, transparent
vulcanization products having satisfactory physical properties can
be obtained by curing. When an ammonium salt, which is readily
releasable or deposable at the secondary vulcanization, is used,
the resulting vulcanization products generate much less gas or
contain much less solvent-extractable components and thus the
present composition has an expected effective use in the medical
field, the food industry, the semiconductor industry, etc.
PREFERRED EMBODIMENTS OF THE INVENTION
The present invention will be explained in detail below, referring
to Examples and Reference Examples.
EXAMPLES 1 AND 2
One part by weight (Example 1) or two parts by weight (Example 2)
of ammonium perfluorooctanoate CF.sub.3 (CF.sub.2).sub.6
COONH.sub.4 was added to 100 parts by weight of terpolymer A of
tetrafluoroethylene/perfluoro(methyl vinyl
ether)/perfluoro(5-cyanopentyl vinyl ether) [molar ratio:
68.0/30.0/1.2] and kneaded through a double roll mill. The
resulting mixture was compression molded at 180.degree. C. for 30
minutes and then subjected to secondary vulcanization in air under
the following conditions:
______________________________________ Example 1 Example 2
______________________________________ Heating at 90.degree. C.
Heating at 90.degree. C. for 4 hours for 4 hours Heating to
204.degree. C. Heating to 204.degree. C. over 6 hours over 6 hours
Heating at 204.degree. C. Heating at 204.degree. C. for 18 hours
for 18 hours Heating to 270.degree. C. Heating to 288.degree. C.
over 6 hours over 6 hours Heating at 270.degree. C. Heating at
288.degree. C. for 18 hours for 18 hours
______________________________________
The resulting secondary vulcanization products had such appearances
as slightly greyish transparent one (Example 1) and colorless,
transparent one (Example 2).
EXAMPLES 3 TO 6
One part by weight (Examples 3 and 4), 1.5 parts by weight (Example
5) or 2 parts by weight (Example 6) of ammonium perfluorooctanoate
was added to 100 parts by weight of terpolymer B of
tetrafluoroethylene/perfluoro(methyl vinyl
ether)/perfluoro(2-cyano-3,7-dioxa-8-nonene) [molar ratio:
72.1/25.5/2.4] and kneaded through a double roll mill. The
resulting mixture was compression molded at 180.degree. C. for 30
minutes and then subjected to secondary vulcanization in air under
the following conditions:
______________________________________ Example 3 Example 4 to 6
______________________________________ Heating at 90.degree. C.
Heating at 90.degree. C. for 4 hours for 4 hours Heating to
204.degree. C. Heating to 204.degree. C. over 6 hours over 6 hours
Heating at 204.degree. C. Heating at 204.degree. C. for 18 hours
for 18 hours Heating to 270.degree. C. Heating to 288.degree. C.
over 6 hours over 6 hours Heating at 270.degree. C. Heating at
288.degree. C. for 18 hours for 18 hours
______________________________________
The resulting secondary vulcanization products all had a
transparent, bright amber appearance.
EXAMPLES 7 AND 8
One part by weight (Example 7) or two parts by weight (Example 8)
of ammonium perfluoro(5,8-dimethyl-4,7-dioxanonanoate) CF.sub.3
(CF.sub.2).sub.2 OCF(CF.sub.3)CF.sub.2 OCF(CF.sub.3)COONH.sub.4 was
added to 100 parts by weight of the above-mentioned terpolymer B
and kneaded through a double roll mill. The resulting mixture was
compression molded at 180.degree. C. for 30 minutes and then
subjected to secondary vulcanization in air under the same
conditions as in Example 2.
The resulting secondary vulcanization products all had a colorless,
transparent appearance.
Reference Examples 1 and 2
0.5 parts by weight (Reference Example 1) or one part by weight
(Reference Example 2) of
2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane was added to 100
parts by weight of the above-mentioned terpolymer B and kneaded
through a double roll mill. The resulting mixture was compression
molded at 180.degree. C. for 30 minutes and then subjected to
secondary vulcanization in air under the same conditions as in
Example 2.
The resulting secondary vulcanization products all had a reddish
brown, opaque appearance.
The vulcanization products obtained in Examples 1 to 3 were
subjected to the following tests:
Normal state physical properties:
Hardness test according to DIN 53505
Tensile test according to DIN 53504 (100% modulus, tensile strength
and elongation)
Heat ageing test: normal state physical properties after ageing at
200.degree. C. for 70 hours in air.
Compression set: ASTM Method-B/P-24 O-ring
Solvent-resistant test: volumic swelling ratio (%) after dipping in
a solvent at a given temperature for 70 hours.
Test results are shown in the following Table 1.
TABLE 1 ______________________________________ Properties Ex. 1 Ex.
2 Ex. 3 ______________________________________ [Normal state
physical properties] Hardness (JIS-A) 63 61 59 100% modulus (MPa)
2.5 2.6 2.5 Tensile strength (MPa) 22.2 21.0 17.8 Elongation (%)
270 270 280 [Heat ageing test] Hardness (JIS-A) 63 62 60 100%
modulus (MPa) 2.6 2.5 2.2 Tensile strength (MPa) 21.3 17.0 16.2
Elongation (%) 259 250 270 [Compression set] 150.degree. C. for 70
hrs (%) 36 34 39 200.degree. C. for 70 hrs 37 40 49 [Solvent
resistant; %] (%) Hexamethylenediamine at +23.4 +13.8 140.degree.
C. Steam at 200.degree. C. +0.9 +1.4 Methyl ethyl ketone at
80.degree. C. +4.5 Methanol at 65.degree. C. +0.9 Ethyl acetate at
80.degree. C. +5.5 30% sodium hydroxide at +0.1 80.degree. C. 60%
nitric acid at 80.degree. C. +0.7
______________________________________
The vulcanization products obtained in Examples 4 to 8 and
Reference Examples 1 to 2 were subjected to determination of
compression set and solvent resistance.
The results are shown in the following Table 2.
TABLE 2 ______________________________________ Compression set (%)
Solvent resistance (%) 150.degree. C., 200.degree. C., H.sub.2
N(CH.sub.2).sub.4 NH.sub.2 Steam Example 70 hrs 70 hrs (140.degree.
C.) (200.degree. C.) ______________________________________ Ex. 4
52 55 +21.6 +0.3 Ex. 5 30 33 +23.6 +1.6 Ex. 6 17 20 +17.3 -0.1 Ex.
7 66 66 +22.7 +1.4 Ex. 8 25 27 +22.9 +0.7 Ref. Ex. 1 26 21 +28.6
+0.5 Ref. Ex. 2 14 14 +39.4 +0.8
______________________________________
EXAMPLES 9 AND 10
One part by weight of triammonium phosphate (Example 9) or one part
by weight of ammonium benzoate (Example 10) was added to 100 parts
by weight of the above-mentioned terpolymer A and kneaded through a
double roll mill. The resulting mixture was compression molded at
180.degree. C. for 30 minutes and then subjected to secondary
vulcanization in air under the same conditions as in Example 2.
EXAMPLES 11 TO 14
One part by weight of ammonium carbonate (Example 11), one part by
weight of triammonium phosphate (Example 12), one part by weight of
diammonium adipate (Example 13) or one part by weight of ammonium
benzoate (Example 14) was added to 100 parts by weight of the
above-mentioned terpolymer B and kneaded through a double roll
mill. The resulting mixture was compression molded at 180.degree.
C. for 30 minutes and then subjected to secondary vulcanization in
air under the same conditions as in Example 2.
The vulcanization products obtained in Examples 9 to 14 were
subjected to observation of appearance, determination of
compression set and solvent resistance test. The results are shown
in the following Table 3.
TABLE 3
__________________________________________________________________________
Solvent resistance (%) Product Compression set (%) H.sub.2
N(CH.sub.2).sub.6 NH.sub.2 Steam Ex. appearance 150.degree. C., 70
hrs 200.degree. C., 70 hrs (140.degree. C.) (200.degree. C.)
__________________________________________________________________________
9 Reddish brown 80 78 20.1 4.8 10 Slight yellow, 52 47 33.5 3.6
transparent 11 Colorless, 75 74 13.5 4.6 transparent 12 Reddish
brown 10 12 23.4 20.9 13 Brown 27 28 11.0 1.6 14 Amber, 46 54 15.9
1.1 transparent
__________________________________________________________________________
* * * * *